Coronal Mass Ejection (CME) on 2013/09/29

A magnificent eruption ejected a massive cloud of solar plasma out away from the Sun, into interplanetary space on September 29th (2013/09/29).  A long filament of plasma hovered above the photosphere, captured by the magnetism in the Sun’s northern hemisphere.  Then, it erupted in spectacular energy as seen by the Solar Dynamics Observatory, and by Stereo and SOHO spacecraft. This plasma eruption produced a stunningly beautiful coronal mass ejection (CME).

Coronal mass ejections are often associated with solar activity such as solar flares, but a causal relationship has not been established. A coronal mass ejection is also produced when a plasma filament (or prominence) breaks away from the magnetic clutch of the Sun, escaping the gravitational pull. While many plasma ejections originate from active regions on the Sun’s surface, such as groupings of sunspots associated with frequent flares, any plasma formation could break away. Near solar maxima, the Sun produces about three CMEs every day, whereas near solar minima, there is about one CME every five days or even less frequently.

When a CME passes Earth (not all CMEs are directed toward the Earth), it could cause geomagnetic disturbances, triggering aurora and causing disruption of shortwave radio communications.

Although this CME was not aimed at Earth, it passed by the Earth with a glancing blow from the plasma cloud on October 2-3 2013. This caused a geomagnetic storm (minor level), which lowered the Maximum Usable Frequency (MUF) over many ionospheric radio-wave propagation paths on shortwave radio.  This lowing of the MUF is often regarded as a
degradation of shortwave radio conditions.  Some aurora is also produced, though this event did not cause much significant aurora.

Here’s a video showing the magnificent plasma eruption and CME:

Credit: SOHO/Stereo/SDO/NASA

More info: and on Facebook at

Aurora Watch:

Visit, subscribe: NW7US Radio Communications and Propagation YouTube Channel

One Response to “Coronal Mass Ejection (CME) on 2013/09/29”

  • Mike VE3WDM:

    Good morning Tomas, until I started to take a closer look at propagation I never realized all the facts about the sun….it’s size..temp and how it can affect more than just radio here on earth.

Leave a Comment

Subscribe FREE to's
Amateur Radio Newsletter
News, Opinion, Giveaways & More!

Join over 7,000 subscribers!
We never share your e-mail address.

Also available via RSS feed, Twitter, and Facebook.

Subscribe FREE to's
Amateur Radio Newsletter

We never share your e-mail address.

Do you like to write?
Interesting project to share?
Helpful tips and ideas for other hams?

Submit an article and we will review it for publication on!

Have a ham radio product or service?
Consider advertising on our site.

Are you a reporter covering ham radio?
Find ham radio experts for your story.

How to Set Up a Ham Radio Blog
Get started in less than 15 minutes!

  • Matt W1MST, Managing Editor

Sign up for our free
Amateur Radio Newsletter

Enter your e-mail address: